Ram use in mavericks

I just bought a rmbp haswell 8gb/256gb and a mba 4gb/256gb.
I noticed that on the rmbp i have 7.5gb used memory with hardly any apps open, just safari.
is this a feature of mavericks?
y is so much memory used?
i know this has been extensively discussed, but apple seems to find only 4gb fit.
even the entry model rmbp has only 4gb. so i assume 4gb should be well enough for the mba.does this also have to do with mavericks (which runs on only 2gb theoretically?

I just bought a rmbp haswell 8gb/256gb and a mba 4gb/256gb.
I noticed that on the rmbp i have 7.5gb used memory with hardly any apps open, just safari.
is this a feature of mavericks?
y is so much memory used?
i know this has been extensively discussed, but apple seems to find only 4gb fit.
even the entry model rmbp has only 4gb. so i assume 4gb should be well enough for the mba.does this also have to do with mavericks (which runs on only 2gb theoretically?

Click to expand...

the ram isn't allocated the same. if you look on the graph in activity monitor it will tell you the "memory pressure" which is how much it is compressing (instead of paging out and back in)

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